Variable v belt pulley drive



March 13, 1952 G. o. TURNBULL VARIABLE V BELT PULLEY DRIVE 2 SHEETS-FEET 1 Filed Dec. 29, 1945 March' 18, 195.2v

Filed Dec, 29, 1949 G. O. TURNBULL VARIABLE V BELT PULLEY DRIVE 2 SHEETS-SHEET 2 IN V EN TOR.

` reduced.

Patented Mar. 18, 1952 Glen O. Turnbull, .Rock Islandrlll., assigner toA International Harvester Company, a corpora*- tion of New Jersey Application December 29, 194.9, Serial No. 135,556

1 This invention relates to a new and improved variable V-belt pulley drive. Variable speeds of Vbelt pulleys are accomplished by changing the space between the pulley 'halves and thereupon causing the belt to ride "lower or higher within the pulley. drive the spaced pulleys carrying the belt must be shifted an equal amount in order that the length of the belt in the driving transmission ren'lains constant. There are various methods of effecting a, shifting of the pulley halves. Near-ly all of these prior` methods or apparatus employ 'direct acting springs for maintaining the pulley halves resiliently together'.v Therefore, upon an increase in load the'pulley halves open up, causing the belt to drop to the bottom of the pulley 'groove and slip, resultingv in loss of torque and damaged belts. In order to overcome this deficienoy in their product these prior manufacturers have increased the spring pressure to handle yoverloads and thusunder normal loading l the belt has to carry excessive side pressure with the result that the belt life is considerably Animportant object of this invention is to prolvidel a variable speed belt drive which will rema'in fixed in any desired position under overload conditions.

Another important object of this invention is the provision of means in a variable V-belt transmission drive for changing the spacingof cooperating pulley halves without a direct application of spring force which tends to cause considerable damage to the belt.

' A still further important object of this inven- 4 Claims. (Cl. '7d-230.17)

tionv is to supply in a belt transmission appara'- tus automatic means for simultaneously shifting Jv'cooperating pulley halves through an equal distance to insure constantly uniform belt tension.

*Swtill another object of this invention is to provide means in conjunction with an automatic device for obtaining uniform belt tension a means 'for manually changing the relative spacings of l'the cooperative belt pulley halves to thereby effect with means for longitudinally shifting the central control shaft so that the Vebelt drive is maintained in proper alignment `with the-spacedvpul- .,leyg..

- Other' and further important objects of this invention will become apparent from the disclojsures inv the following specication and accompanying drawings.

In the drawings:

Fig. l is a top plan view partially in section of the variable V-belt drive of this invention.

AFig. 2- is a sectional view taken on the line 2-5--2 of Fig. l.

Fig-.3 is a sectional View of a portion of the device taken on the line 3-3 of Fig. l. 'f

As shown in the drawings:

The reference numeral I0 indicates generally. supporting structure having a driving shaft' Il journaledV in one portion thereof and'a driven shaft VI2v lying parallel to and spaced from the driven shaft II and similarly journaled within the supporting structure I0. The V-belt pulley I3 is mounted over the driving shaft I I and simllarly a V-belt pulley I4 is mounted over the driven shaft I2. By means of a V-belt I5 drive istransmitted from the shaft I'I to the shaft I2, both of which are journally mounted in the supporting structure I0,

' The V-belt pulley I3 is provided with opposed half sections I6 and I1. The pulley halfv is provided with a hub portion Ill-adapted to surround theshaft II. A key I9; joins the hub I8 to the shaft II forconcurrent rotation of these parts. A ball bearing 2li is disposed between thesupporting structure I0 and the end of the pulley half hub I8 as well as encircling the shaft II. The bearing 20 thus is conducive to the rotation of the shaft and hub` with respect to the stationary'supportins structure l0.

A sleeve 2 Il is mounted on the shaft I I andentends from a position adjacent the hub I 8y to substantially the end of the shaft. A ring or washer-like. member 22 surrounds the sleeve 2l adjacent its inner end and is welded thereto as shown at 23.. The ring is fastened by meansv of rivets 24 tothe pulley half I6. Itis thus apparent that as. the shaft I I is rotated the pulley half IS is similarly being rotated along withr its integral parts, the sleeve 2| and the ring 22.,

The outer surface ofthe sleeve 2| is externally splinedto slidably receive an internally splined sleeve 25 which constitutes a hubv for the pulley half I'I. The sleeve 25 has an outwardly entende ing annular ange 26 which isfastened to the pulley half Il by means of rivets or the like 2l. The pulley half I'I is formed Ywith an axially extending annular lip 28 concentric with the shaft I I for the purposeof receiving aball beariifigy 2S. The outer race 30 is press=fltted Within the, ,sleevelike lip 28 and abuts a shoulder 3l. formed in the outer end of the inner race 32 of the ball bearing" 29. threaded portion 96. The threads 96 have a pitch designed for self-locking. The sleeve 94 alsoY contains a sprocket 91 positioned thereover and welded to the sleeve as shown at 98.

A stationary sleeve 99 surrounds the hub 25 of the pulley half I1. The sleeve 99 is provided with an outwardly extending annular flange |09 at the outer end of the sleeve and is equipped with an opening I'0I` for receiving a-bolt |02 for fastening -tothe yoke supporting member 35. The sleeve The other end of the sleeve 94 contains' a from the pulley half 40.

-99 forms a bearing support for the sleevemelnber i cause concurrent rotational drive of both pulley 94. The sleeve 99 being concentric with the shaft v|I.permits relative longitudinal'and rotational movement of the sleeve memberv 94. A second stationary sleeve |03 is spaced'outwardly from the stationary sleeve 99 and concentric therewith. 4The sleeve |93 is similarly provided with an outwardlyv extendingA annular flange |04 and as shown in thedrawing the'flanges |04 and |00 nest against each other and the bolt |02 simul- -taneously holds the sleeves 99 and |03 rigid with respect to the yoke member 36. The yoke aspre- -viously stated forms a part of the supporting structure I0 and thus the concentric guiding manner as the supporting structure I0. f j The inner surface of the sleeve |03 is provided 4with'tllreads |05 to mate with the threads 95 of lthe operating sleeve member 94. Rotation of the *sprocket 91 and thus also the sleeve 94 will cause th'esleeve to more or less threadedly engage the Ainternal threads |05 of the outer guide sleeve |03.

. l35 `sleeves 99 and v|03 are stationary ln the same In the position as shown in the drawing, the mov- .able pulley half I1 is shown in its closest relation- 'ship'with its cooperative pulley half IB and thus the operating sleeve 94 is in its maximum withdrawnposition from the internally threaded .sleeve |03. VRotation of the-sprocket 91 to cause a movement of thesleeve 94 away fromthe inner ,race 32 of the ball'bearing 29 permits a V-belt riding inthe pulley I3 to cause a spreading of the .pulley half I1 so that in fact the inner race 32 of the bearing will closely follow the retracting`Y sleeve 94. When the pulley half I1 is in a spaced apart position from its cooperative pulley half I6 Vrotationalfmoven'lent of the sprocket 91 in a directionl to. cause the .sleeve 94 to move outwardly .from the threads|05 causes the sleeve to contact the bearing 29 andthereupon impart a direct .axial force on the pulley half I1 thereupon causring member 44 is welded to the sleeve 43 at 45 and forms an outwardly extending flange for the 'sleeve43. The ring member 44 is fastened to the pulley half 49by means of rivets 45. Thus, as vthe'pulley half 40 is rotated the structure in- "cluding the sleeve 43, ring 44, and the shaft I2 will similarly rotate.

I4 includes' 'a pulley half.H

Yby the annular clearance 62.

A nut 41 threadedly engages the end 48 of the shaft I2 and through the medium of a washer 49 maintains the pulley structure on the confines of the shaft I2. The V pulley I3 and its associated structure is also maintained on the shaft I I against endwise movement by means of a nut 50 upon threadedly engaging the end 5| ofthe shaft II. The nut 5I) maintains a washer 52 against the sleeve 2| thus holding the sleeve against axial movement oI the end of the shaft I I.

The pulley I4 also includes a pulley half 53 adapted for sliding movement toward and away The sleeve A43 is externally splined to slidably receive an linternally splined sleeve 54. The sleeve 54 has an outwardly extending annular flange 55 which is fastened by means of rivets 53 to the pulley half 53. Thus the pulley half 53 with its integral sleeve hub 54 may be moved along the splined sleeve 43 with respect to the pulley half 40 and yet regardless of the position ofthe pulley half 53 the interengaging splines between the members 43 and 54 halves 40 and 531 This, of course, is similar to the half I1 is'movable toward and away .from the pulley half I6, maintaining concurrent drive of .both pulley halves.

The movable pulley half 53 is equipped-with -anintegral annular lip or sleeve portion 51 vspaced from and concentric to. the shaft I2 for receiving a ball bearing 58. The outerrace 59 of the bearing 58 is press-fitted within the sleeve 51 and its inner end abuts a shoulder 60. The inner race 6| of the bearing 58 surrounds the sleeve hub 54 but is slightly spaced therefrom as shown An inner guide sleeve |06 is journally mounted around the movable pulley half hub 54. The sleeve |03 is provided with an outwardly extending annular flange |01'which is rigidly fastened to the supporting structure I0. A second or outer guide sleeve |08 is internally threaded as shown at |09 and siml- .larly has an outwardly extending annular-flange .I I0 Yfor attachment to the supporting. structure VIII. The flanges |01 and ||0 are adapted to lie one upon the other and journal members I I pass through apertures ||2 and I|3 in the flanges IIII .and |01 respectively and engage a' threaded socket I I4 inthe supporting structure I il. Thus the con- Acentric guide sleeves |06 and IIIIl-arel rigid with respect to the supporting structurev I0 and the movable half 53 ofthe pulley is .arranged for vmovement with respect to these stationary contact engagement of the-inner race 6I of the ball bearing 58.

sleeves.

An operating sleeve II5 has an'lend IIS for The operating sleeve'I I5 there- '#fore .effects shifting movement ofthe-.pulley half vly determine .the spacing of the pulley halves.

The pitch of the cooperative threads |09 and I|1 is very low and thus there is a minimum possibility of relative rotational movement of the vsleeves `I I5 and |08 merely upon the application of 'an axialforce applied tov the sleeve I5. .In

other words, the pitch provides a self-locking 5 screw. A centrally positioned control shaft |20 is carried in bearings I 2| and |22. The bearings are carried on the stationary supporting structure I by means' of a suitable'bracket |23. The shaft |20 carries spaced sprockets |24 and |25 which 'are' in alignment respectively with the sprockets 91 and ||8 respectively. The sprocket |24 pinned or otherwise fastened to the shaft |20 is equipped with a` unitary hub |26 and a lpin |21which passes throughthe hub and the shaft |20, making the connection between the sprocket |24' and the shaft Vfixed. The sprocket |24 thus cannot have relative rotational movement with respect to the shaft |20 nor can lit move longitudinally on the shaft, 20.

"I'h'e Sprocket |25 is similarly provided with-'e laterallyextending hub |28 but is permitted relative rotational Amovement on the shaft |20. The hub |28 thus acts merely as a sleeve bearing'for the sprocket |25 in its mounting on the shaft |20. The inner ends of the oppositely and inwardly extending hubs |26 and |28 abut each other to maintain a fixed spacing between the sprockets |24 and |25. A thrust collar |29 is fastened to the shaft |20 as shown by the cross pin |30.

Radially extending ears or lug members |3| and |32 are provided on the hub members |26 and |28respectively. The lug members I3I and |32 are inclined toward each other and overlap sufficiently so that a shaft member |33 may pass through aligned apertures |34 and |35 in the lue members'v I3I and |32 respectively as `best shown in Fig. 2. The shaft |33 is in the form of a bolt member having a head |36 and an adjustable nut |31 at the outer end thereof. A coil spring |36 is disposed between the bolt head |36 and the lug member |32, and similarly a coil spring |39 is disposed between the nut |31 and the lug |3| The overlapping lug members |3| and |32 are three in number and are evenly disposed around -f the periphery of the sprocket hubs |26 and |28. The springs |38 and |39 act to impart rotation to the sprockets |24 and I 25. Chains |40 and |4| join the sprockets IIB and |24 and |25 and 91 respectively. The springs through the medium of the chains |40 and |4| tend to rotate the sleeves and 94 in such a manner to provide take-up lfor wear of the V-belt I5 and to provide a constant tension for the belt. The variable V-belt pulleys of this invention are arranged so that as the pulley half of one pulley is moved away from its cooperative pulley half the movable pulley half of the other pulley is drawn closer to its cooperative pulley half and each movable half travels through an equal distance.

The length of the V-belt I5 remains constantl throughout the entire graduation of driving ratios between the driving and driven pulleys. The adjustment for belt wear and for maintainlng constant tension is accomplished automatically by the coil springs '|38 and |39 which tend to move the lugs |3| and |32 toward each other.

In the operation of the device driving ratio between the pulleys I3 and I4 is changed merely by pulling one of the chains |40 or I4| in the direction desired and there will be a shifting of the pulley halves I1 and 53 in an equal direction and oppositely with respect to their fixed pulley halves I6 and 40 respectively whereupon the V-belt I5 may ride in any desired position within the grooves of the pulleys I3 and I4. Variations in spacings of the pulley halves require a shifting of the central operating shaft I 20 and this is accomplished by means of a pin |42 fastened to the shaft |20 and extending outward- 6, ly therefrom and adapted tov ride in a spiral shaped cam track |43 in' the 'bearing sleeve |22; Rotation of the shaft |20 thus causes a move-r. Ament of the pin |42 in the spiral cam groove |43 resulting in longitudinal shifting movementaof the shaft |20. Thus the sprockets|24 and .|25

'are' maintained in correct alignment with.the

sprockets II8 and 91'respectively. Rotation of the operating shaft |20 may .':bc made in numerous ways. As shown in Fig. 3,;the rotation of the shaft |20 is accomplishedby a toothed rack |44 and pinion |45; '.-Side bracket plates |45 and|41 are'journallyrrnounted over the shaftff|20 through aligned openings therein |46 and |49. The spaced plates |46 and |41 carry guide rollers |50 and .|5I therebetween.,on the side of the plates spaced from and journally mounted onjthe shaft |20.. The rollers |50 and 15| 'are carried in the plates by means of' shaft pins |52 and |53 which's'pan the plates |46 and |41. The guide rollers are'adapted to engage the backsurfa'ce |54 of the toothed rack |44 -and maintain the rack in engagement with-the pinion |45. As the rack |44 is manually shifted the pinion |45 will be rotated and as previously stated as the shaft |20 is rotated it is simultaneously moved axially because of the pin |42 engaging the cam track |43 in the bearing |22.

It is believed that herein is provided a variable V-belt drive transmission which will remain in fixed selected position regardless of overload conditions inasmuch as the pulley halves are not subject to direct action by yieldable spring means. -The pulley halves thus will not open up under extreme loads causing the belt to ride in the bottom of the groove and slip, which invariably results in' loss of torque and damaged belts. The spring pressure at the central control sprockets provides only enough pressure to maintain proper belt tension and compensation for wear. When the full travel of the springs |38 and |39 has been used for take-up, a new start is made by shifting one chain on the sprocket one tooth.

Various details of construction may be varied throughout a wide range without departing from the principles disclosed herein and I therefore do not propose limiting the patent granted hereon otherwise than as necessitated by the appended claims.

What is claimed is:

1. A variable V-belt pulley drive comprising a supporting structure, spaced parallel shafts journaled in said supporting structure, V-belt pulleys mounted on each of said shafts, each of said pulleys having complementary halves, one of each of said pulley halves having means cooperating therewith for effecting movement toward and away from their respective complementary pulley halves, a control shaft journaled on said supporting structure and disposed between the pulley shafts, said means for effecting movement of the pulley halves including a pulley half hub splined on each of said spaced shafts, a sleeve journaled for separate rotational movement on said hub, said sleeve arranged and constructed for joint llongitudinal movement with said hub, said sleeve having a low pitch thread engageable with a correspondingly pitched thread on said supporting structure whereby rotational movement of said sleeve Will effect longitudinal sliding movement of the sleeve and hub along said shaft, a sprocket mounted integrally with each of said sleeves, a pair of spaced sprockets carried on said control shaft so that one of the pair of sprockets is in alignment with one of the sprockets on one sleeve and the other of said pair of sprockets is in alignment with the sprocket on the other sleeve. chain means joining the aligned sprockets,`hub members forming a part of each of the pai r 'of sprockets on the control shaft, one of saidpair of'sprockets and its hub flxedly fastened to said control shaft, spring means interposed between said fixed sprocket and the other of said pairfof sprockets, a V-belt extending around the spaced pulleys, said interposed spring means tending to maintain a constant tension on said belt without permitting the pulley halves to open up' on direct outward belt forces on the movable pulley halves. y .E

2. A device as set forth in claim l in which vthe interposed spring means includes inwardly inclined lug members on each of said sprocket The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,170,838 Rossman fAug 29,l 1939 2,195,952 Capocefalo -'L Apr. 2, 1940 2,199,491 Heynaud YMay 7, 1940 2,259,567 Johnson Oct. 21, 1941 2,262,782 Strom Nov. 18, 1941 2,267,566 Johnson Dec. 23,1941

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